Measuring the mechanical axis of the lower limbs of children with telemetric radiographies and photographic camera by determining correlation of the two methods

Abstract

Genu Varum and Genu Valgum in children in many cases, don't have required further treatment but in many cases, to ensure that the problem is benign, telemetric radiography is necessary. In some cases, this radiograph should be repeated to determine the rate of recovery or follow up treatment. On the other hand, the radiography, especially in children, has side effects due to x-rays. Therefore, this study has been designed to calculate the angles of varus, valgus and the mechanical axis of the lower extremity by telemetric radiography and digital photography, and then their correlation was compared. Methods and materials: In this prospective descriptive-analytic study, 92 patients between 2017 and 2018 were evaluated who were referred to the Shohada educational and therapeutic center with deformities of the lower limbs. After specifying of the ASIS (Anterior Superior Iliac Spine), the middle of Patella, knee and ankle, digital radiographs of the whole body under standardized conditions and telemetric radiography (after marking with chest lead) were taken and then, coloration of the angles were compared. Results: The mean absolute dif¬ference between the mechanical axis angle (G) and the obtained result of digital photography (B and C angle) were calculated by the telemetric radiogra¬phy method and the digital photography method respectively (B= 3.5(right side), 3.6(left side) and C= 4.1(right side), 3.1(left side)). The strongest correlation was between B (left) and G (left) angles which indicates a significant correlation between the mechanical angle GL (the telemetric radiograph) and BL angle (digital photography). Also, the ratio of the E line to D (the distance of the point of ASIS in the desired side to the intersection point of the perpendicular line to the center of the femoral head in the same side) was obtained 1/6.